#!/bin/python

import sys


n = int(raw_input().strip())
xr = []
yr = []
for a0 in xrange(n):
    x,y = raw_input().strip().split(' ')
    x,y = [int(x),int(y)]
    xr.append(x)
    yr.append(y)

xi = xr[0]
yi = yr[0]
line1 = "YES"
line2 = "YES"
for i in xr:
    if i != xi:
        line1 = "NO"

for i in yr:
    if i != yi:
        line2 = "NO"
        
if(line1 == "YES" or line2 == "YES"):
    print "YES"
else:
    print "NO"